> Download and Print Article

You’ve probably heard the debate: some people say seed oils are harmful and should be avoided, while others claim they’re a healthier alternative to saturated fats like butter. So, who’s right? Both sides present convincing arguments, but here’s my take: seed oils aren’t automatically bad—and in this article, I’ll explain why. The real problem lies in how these oils are processed and the excessive amounts people consume today. That’s where the real concern begins.

In this article, I will walk you through some of the most common cooking oils I recommend limiting or avoiding and explain why. And if you think you’re not eating seed oils, think again. For example, the most widely consumed edible oil in the United States is soybean oil—a seed oil that’s high in a polyunsaturated fat called linoleic acid (pronounced lin-oh-LAY-ik), a type of omega-6 fat. The real issue isn’t simply that it contains linoleic acid, or that it’s categorized as a “seed oil.” The concern lies in how the oil is made and how much you may be consuming on a regular basis.

When it comes to seed oils, it’s not just soybean oil in question—many commonly used oils in cooking and packaged foods are high in linoleic acid, the omega-6 fat that defines most seed oils. The truth is that linoleic acid isn’t just in the frying pan. It shows up in everything from mayonnaise, chips, and salad dressings to granola bars and even foods marketed as “healthy.” Over time, these oils have quietly become a major part of the modern diet. As mentioned earlier, the concern isn’t occasional use—it’s the daily, repeated exposure to linoleic acid from multiple ultra-processed sources that adds up and raises red flags for our health.

To simplify things and help you easily identify oils high in linoleic acid (at least 20%), I created what I call the “Terrible 10”—a list of common cooking and ultra-processed oils I consider potentially harmful. Why “potentially harmful”? Because these oils have been shown to disrupt the omega-6 to omega-3 balance, reduce red blood cell membrane fluidity, and increase levels of arachidonic acid (AA). These biological shifts are not just associated with—but are known to contribute to—insulin resistance, chronic inflammation, narrowing of the arteries, and increased all-cause mortality, to name a few.

How Seed Oils Are Made—and the “Terrible 10”

Seed oils don’t just flow out of seeds like juice from a fruit. To extract every drop, companies use machines and chemicals in a process called Refined, Bleached, and Deodorized (RBD). But it wasn’t always this way.

Take sesame oil, for example. Although it’s technically a seed oil, traditional cultures in India, China, Korea, Japan, Ethiopia, and the Middle East used a completely different method. For thousands of years, they gently pressed sesame seeds—without heat or chemicals—to produce small amounts of oil, mainly used for flavoring, not for deep frying or to be an added ingredient to ultra-processed foods (e.g., cereal, mayonnaise).

When sesame oil is made this traditional way, it preserves powerful antioxidants like sesamol and sesamin, which help protect both the oil and your body. In contrast, modern seed oils go through intense industrial processing that strips away nutrients and creates harmful byproducts.

Here’s how modern seed oils are typically made:

• • Solvent Extraction: A chemical called hexane is used to extract the oil.
  • High Heat: The oil is heated to extreme temperatures, which can damage the fats.
  • Bleaching: Natural color is removed through chemical bleaching.
  • Deodorizing: Strong odors are eliminated—because by this stage, the oil may already be rancid.

By the time these oils reach store shelves, they’ve often lost most of their beneficial nutrients and may already contain harmful compounds formed during processing. To make matters worse, we usually heat them again—especially in deep fryers at restaurants—further degrading their quality. And here’s the real problem: by the time you purchase these oils or consume products made with them, the oils have likely already been oxidized.

Oxidized means the oil has reacted with oxygen, which causes it to break down and form unstable molecules called free radicals. These free radicals can trigger inflammation and damage cells in the body—raising the risk for chronic diseases like heart disease, cancer, and insulin resistance.

Before I introduce the “Terrible 10,” I want to address a common counterpoint from those who defend seed oils: the claim that many manufacturers add synthetic antioxidants—like BHT or TBHQ—to extend shelf life. While that’s true, these additives do not fully prevent oxidation.

Take mayonnaise, for example. Oxidation is almost inevitable unless it’s freshly made using cold-pressed oil. That’s why I recommend choosing “extra virgin” oils whenever possible—because by definition, extra virgin means the oil was cold-pressed, a process that preserves nutrients and minimizes oxidation.

Another important tip: to reduce oxidation after bottling, store oils in dark glass containers, keep them cool, and use them promptly. These steps help maintain the oil’s integrity and health benefits.

To help you identify these seed oils that I recommend avoiding, we created the “Terrible 10”, which includes the ones with the highest levels of linoleic acid:

 When it comes to cooking oils, instead of the “Terrible 10,” I recommend using extra virgin olive oil, extra virgin coconut oil, extra virgin avocado oil, and extra virgin palm oil. I also encourage the use of grass-fed butter, grass-fed ghee, and grass-fed beef tallow.

As beef tallow grows in popularity, choose organic when possible, and look for tallow that’s rendered at low temperatures. Likewise, with ghee, opt for grass-fed and small-batch clarified for better quality. And as with most foods, aim to buy from trusted, transparent sources as you become familiar with different brands.

When Too Much of a Good Thing Becomes Bad

I opened this article by clarifying that not all seed oils are inherently bad. Traditional methods of extracting oils—such as gently pressing sesame seeds—aren’t the problem as I shared earlier. So, we can all agree that when made naturally (without machines and chemicals where the oils are made through the process identified as Refined, Bleached, and Deodorized) and used in small amounts, these oils can be part of a healthy diet.

Few people would argue that modern-day seed oils—typically produced using industrial methods involving chemical solvents, high heat, and intense pressure—are actually good for you. While it’s true that linoleic acid is essential in small amounts for proper bodily function, the problem arises when we consume too much, especially from refined and oxidized sources.

Research has shown that excess linoleic acid from these sources contributes to chronic inflammation, which is a well-established driver of many serious health conditions, including:

• • Heart disease
  • Obesity
  • Type 2 diabetes
  • Certain cancers

But Here’s the Issue:

• • Decades ago, people consumed only about 1% to 2% of their calories from omega-6 fats.
  • Today, that number is 10% to 20%, with most of it coming from seed oils in processed foods.

That’s a massive jump—and it matters. Another point to reinforce is that linoleic acid is highly unstable, meaning it oxidizes easily when exposed to heat (like during cooking) or air (during storage). When that happens, it forms toxic byproducts like aldehydes—harmful compounds linked to:

• • Inflammation
  • Weight gain
  • Heart disease
  • Even cancer

So, while linoleic acid isn’t harmful on its own, the problem arises when it’s consumed in excessive amounts, especially from industrially processed seed oils. And for those who continue to defend seed oils without considering how they’re manufactured—pause and think about this: what does it actually take to produce just one tablespoon of seed oil?

Remember the old saying: “The poison is in the dose.” Keep that in mind as you read on.

It Takes WAY Too Much to Make a Little Oil

The numbers are eye-opening:

• • Corn oil: About 30 ears of corn
  • Grapeseed oil: Roughly 250 pounds of grapes (just for the seeds!)
  • Sesame oil: Over 1,000 sesame seeds

In nature, no one ever consumed oil from hundreds or thousands of seeds at once. Yet today, people unknowingly eat multiple tablespoons of seed oils every day in ultra-processed foods like:

• • Fried snacks
  • Bottled salad dressings
  • Granola bars
  • Plant-based meats
  • Packaged sauces and dips

This is why it’s so easy to overconsume linoleic acid—and why it’s become a modern health concern.

Whole Foods with Linoleic Acid Are Safe

I get it—at times it may sound like I’m flip-flopping: one moment I say seed oils have benefits, and the next I warn you to avoid them. But here’s the hardcore reality: linoleic acid from whole foods is naturally beneficial. You’ll find it in nutrient-rich, unprocessed foods like:

• • Walnuts
  • Almonds
  • Sunflower seeds
  • Egg yolks

In these whole foods, linoleic acid is packaged with fiber, vitamins, minerals, and antioxidants—all of which help your body stay in balance. The problem starts when linoleic acid is isolated, heavily processed, and consumed in large amounts without those natural protective compounds. That’s when it becomes a problem for your health.

Final Thoughts: What You Can Do

Seed oils may seem normal because they’re in so many everyday foods—but they’re not natural anymore. They’re made in big factories using chemicals and high heat, and they’re eaten in large amounts, every day.

Here’s how you can make better choices:

• • Use oils extra virgin oils (e.g. olive, coconut, palm, avocado), grass-fed butter, grass-fed ghee, grass-fed beef tallow (opt for organic when possible)
  • Eat omega-3-rich foods like wild salmon, walnuts, and flax seeds
  • Cut down or avoid ultra-processed foods with “hidden” seed oils

The more you eat real, whole foods, the better your body will feel. You don’t have to fear fat—you just have to choose the right kind.

Get Tested

Whether you’re pro seed oil or skeptical of them, one of the smartest next steps you can take is to get tested—and find out if the way you’ve been eating is truly working for your body.

The test I recommend is the BalanceTest—a simple, at-home dried blood spot test that delivers powerful insights into key health markers, including:

• • Your omega-6 to omega-3 ratio
  • Red blood cell membrane fluidity
  • Arachidonic acid (AA) percentage

These aren’t just numbers on a page. They are real biomarkers that reveal your risk for:

• • Chronic inflammation
  • Insulin resistance
  • Cardiovascular disease

And if you’ve been unknowingly consuming excessive seed oils, this test will show it. If you’re out of balance, you’ll know—and most importantly, you’ll know what to do about it.

Test, Improve, Retest

Once you take the BalanceTest and get your results, the next step is to start making small but powerful changes:

• • Reduce intake of ultra-processed seed oils
  • Increase your intake of omega-3-rich foods
  • Add more fiber, polyphenols, and antioxidants to your diet
  • Stay hydrated and move your body daily

Then, retest in 120 days. Why? Because your red blood cell membranes regenerate approximately every four months. A retest will verify if your lifestyle changes are actually working—with objective data, not guesswork.

Consider BalanceOil+

To increase your chances of better results on your next test, I highly recommend BalanceOil+. This isn’t your average fish oil. And in full transparency—I endorse BalanceOil+, sell it, and proudly serve on the Health and Product Advisory Board for Zinzino, Inc., the company that manufactures it.

Why do I stand behind it so confidently? Because I’ve personally witnessed hundreds of my nutrition clients benefit from it—with measurable improvements in their test results, overall health, and quality of life. I believe in it wholeheartedly because it works.

BalanceOil+ is a scientifically formulated blend of:

• • Wild-caught fish oil (rich in EPA and DHA omega-3s)
  • Cold-pressed, extra virgin olive oil (loaded with polyphenols)
  • Natural vitamin D3

This combination not only increases your omega-3 levels but also protects your cells from oxidation, enhances membrane fluidity, and helps balance your omega-6 to omega-3 ratio.

Unlike typical fish oils, BalanceOil+ includes polyphenols, which act as natural antioxidants to protect and “chaperone” the omega-3s into your tissues more effectively.

Learn More

To learn more about the BalanceTest and how to get started, contact the person who shared this article with you, or email me directly at: robert@dietfreelife.com

Your health deserves data.
Your body deserves balance.
Let’s make it happen—one test at a time.

References

1. 1. Blasbalg, T. L., Hibbeln, J. R., Ramsden, C. E., Majchrzak, S. F., & Rawlings, R. R. (2011). Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century. The American Journal of Clinical Nutrition, 93(5), 950–962. https://doi.org/10.3945/ajcn.110.006643
   2. Ramsden, C. E., Zamora, D., Majchrzak-Hong, S. F., Faurot, K. R., Broste, S. K., Frantz, R. P., … & Hibbeln, J. R. (2016). Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from the Minnesota Coronary Experiment (1968–73). BMJ, 353, i1246. https://doi.org/10.1136/bmj.i1246
   3. Spiteller, G. (2006). Peroxyl radicals: inductors of neurodegeneration and aging. Archives of Physiology and Biochemistry, 112(4-5), 265–276. https://doi.org/10.1080/13813450601059837
   4. Monteiro, C. A., Cannon, G., Levy, R. B., Moubarac, J. C., Louzada, M. L. C., Rauber, F., … & Jaime, P. C. (2019). Ultra-processed foods: what they are and how to identify them. Public Health Nutrition, 22(5), 936–941. https://doi.org/10.1017/S1368980018003762
   5. Hulbert, A. J. (2005). On the importance of fatty acid composition of membranes for aging. Journal of Theoretical Biology, 234(2), 277–288. https://doi.org/10.1016/j.jtbi.2004.11.024
   6. Small, D. M. (1991). The effects of glyceride structure on absorption and metabolism. Annual Review of Nutrition, 11, 413–434. https://doi.org/10.1146/annurev.nu.11.070191.002213
   7. Nagasaka, R., Chotimarkorn, C., Shafiqul, I. M., & Hori, M. (2007). Antioxidative effects of sesamin against lipid peroxidation in rat liver. Food and Chemical Toxicology, 45(11), 2405–2410. https://doi.org/10.1016/j.fct.2007.06.016
   8. Mozaffarian, D., Micha, R., & Wallace, S. (2010). Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Medicine, 7(3), e1000252. https://doi.org/10.1371/journal.pmed.1000252
   9. Calder, P. C. (2008). Polyunsaturated fatty acids, inflammatory processes and inflammatory bowel diseases. Molecular Nutrition & Food Research, 52(8), 885–897. https://doi.org/10.1002/mnfr.200700289
   10. Grootveld, M., Silwood, C. J., Winter, W. T., & Spickett, C. M. (2014). Health effects of oxidized heated oils. Food Chemistry, 123(4), 923–930. https://doi.org/10.1016/j.foodchem.2010.04.079
   11. Schindler, W. (2021). Eat Like a Human: Nourishing Foods and Ancient Ways of Cooking to Revolutionize Your Health. New York: Little, Brown Spark.

_______________

Robert Ferguson is a California- and Florida-based single father of two daughters, nutritionist, researcher, best-selling author, speaker, podcast and television host, health advisor, NAACP Image Award Nominee, creator of the Diet Free Life methodology, and Chief Nutrition Officer for iCoura Health. He also serves on the Presidential Task Force on Obesity for the National Medical Association and the Health and Product Advisory Board for Zinzino, Inc.

You can reach Robert via email at robert@dietfreelife.com.

🗓️ Schedule a FREE consultation with Robert Ferguson about becoming a client: SCHEDULE FREE CONSULTATION

👉🏽 To order ONLY the BalanceOil+, > CLICK HERE

👉🏽 To order the BalanceOil+ with the BalanceTEST, > CLICK HERE

👉🏽 Watch a free online presentation on the BalanceOil+ and the BalanceTEST: WATCH NOW.